From 3d77f13bff0bb7b47384a748f3bf080d59dd22da Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Fri, 6 Oct 2017 18:19:37 +0300
Subject: [PATCH] Copy BitStrings tuple, do not reference it

---
 pyderasn.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pyderasn.py b/pyderasn.py
index 833e785..d14997b 100755
--- a/pyderasn.py
+++ b/pyderasn.py
@@ -1656,7 +1656,10 @@ class BitString(Obj):
 
     def copy(self):
         obj = self.__class__(_specs=self.specs)
-        obj._value = self._value
+        value = self._value
+        if value is not None:
+            value = (value[0], value[1])
+        obj._value = value
         obj.tag = self.tag
         obj._expl = self._expl
         obj.default = self.default
-- 
2.44.0